CPU is sensitive to hot air going trough radiator. On the other side CPU doesn't release so much heat that can drastically increase GPU temps. On better ventilated cases you can pretty much run the AIO wherever you like, and not see much difference. But in the bad airflow cases like Entho EVOLV CPU just gets choked in all that hot air from GPU. It all depends on many factors, but in that chassis it makes a difference.

I'll give that a watch now. Is it really needed to remove the mesh at the top of the case, as you described previously? Rather not remove it. Cheers for your help

When you remove the top from that case you get 10+ temperature on all components. That is a serious restriction. Either way it is not rigid tubing loop. Try putting AIO top and front, Push/Pull, only Push. You can also remove the top of the case in those situations and see what benefits you best. Run 30 mins of Valley benchmark on each instance and follow temps and noise. It is balance between temperatures, and noise that matters, but it is subjective where are you happy with those values. Setting up your system is part of having top end components. You can ramp all fans on max if you don't want silence, and temps will be good.

X62 is the same Asetek unit as H115i. NZXT did a custom PCB on theirs, and added fancy RGB light. They perform pretty much the same, with the difference that the pump on X62 is quieter than H115i.

With Entho EVOLV TG i would recommend you to put AIO at the front with Push/Pull because that case has very restricted exhaust. Cover all the space not used by fans on top fan mounting plate. Peal mesh from cutouts at top panel, and try to remove grill that is on the back just beneath top panel.

This.

You can pull the top panel off the EVOLV slightly and let it sit on the pegs that hold the panel in place. This might not look as sleek, but your exhaust will work a lot more efficiently. So many examples of users with high temperatures are down to poor ventilation in what are generally regarded as excellent cases. Simple changes can make the world of difference. Adding fans is what people usually go for, but sometimes removing an unnecessary dust filter can be not only cheaper and easier but also derive better results.

As far as AIO's, I'd rather go for the NZXT. The extra tubing length would be perfect if you front mount the radiator. The NZXT has a quieter pump so I've read. I think it looks sexier. And the fans are a little better this time around. Performance is negligible. The differences between AIO's at this point is price, aesthetics, availability, warranty, and noise (even then noise is often very similar). AIO's have hit their peak performance I think. I can't see them getting any better until Asetek manage to build a quiet pump as good as a Laing DDC or D5.

I've run my AIO in the front as intake and top as exhaust and it makes pretty much zero difference to my CPU performance. 2-3 degrees more heat on the CPU so if you're running overclocked then it's worth thinking about, otherwise it's whichever aesthetic you want.

My GPU's get pretty warm so with the AIO exhausting then I'd probably get a few more MHZ before they throttle than as an intake (with the GPU's breathing warm air) but I just like the look of it in the front.

I have a magnetic dust filter on the top of my case and removing it will help the temps more than changing the AIO location. Like AngryGoldfish said it's all about ventilation and planning. With my old 500R I'd pull the front and top panels off on hot days. Ugly but effective.

The idea of putting some spacers between the top panel and the chassis is a great fix.